Flowability Modification of Lactose Powder by Plasma Enhanced Chemical Vapor Deposition

Abstract

The surface of 5.5 µm lactose particles was modified by gas phase reactions in a plasma enhanced chemical vapor deposition process to increase the flowability of the bulk solid. The particles were treated in the radio frequency plasma zone (RF) of a downer reactor, using a process gas mixture of oxygen, argon, and hexamethyldisiloxane (HMDSO). By increasing the flow rate of HMDSO (17–103 sccm) and the RF-power (50–200 W), respectively, the flowability can be increased up to a factor of 2 compared to the untreated substrate material. No significant change in flowability was observed by varying the oxygen-to-HMDSO ratio from 5 to 30.